/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Collections;
using Spring.Util;

namespace Spring.Dao.Support;

/// <summary>
/// Miscellaneous utility methods for DAO implementations.
/// Useful with any data access technology.
/// </summary>
/// <author>Mark Pollack (.NET)</author>
public class DataAccessUtils
{
    /// <summary>
    /// Initializes a new instance of the <see cref="DataAccessUtils"/> class.
    /// </summary>
    public DataAccessUtils()
    {
    }

    public static object RequiredUniqueResultSet(IList results)
    {
        int size = (results != null ? results.Count : 0);
        if (size == 0)
        {
            throw new EmptyResultDataAccessException(1);
        }

        if (!CollectionUtils.HasUniqueObject(results))
        {
            throw new IncorrectResultSizeDataAccessException(1, size);
        }

        IEnumerator enumerator = results.GetEnumerator();
        enumerator.MoveNext();
        return enumerator.Current;
    }

    /// <summary>
    /// Return a translated exception if this is appropriate, or null if the exception could
    /// not be translated.
    /// </summary>
    /// <param name="rawException">The raw exception we may wish to translate.</param>
    /// <param name="pet">The PersistenceExceptionTranslator to use to perform the translation.</param>
    /// <returns>A translated exception if translation is possible, or or null if the exception could
    /// not be translated.</returns>
    public static DataAccessException TranslateIfNecessary(Exception rawException, IPersistenceExceptionTranslator pet)
    {
        AssertUtils.ArgumentNotNull(pet, "PersistenceExceptionTranslator must not be null");
        return pet.TranslateExceptionIfPossible(rawException);
    }
}
